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Unlocking the Genetic Mysteries of Alcoholism

May 19, 2000 (Chicago) -- We all know heredity plays a big part in alcoholism. We've seen the patterns that run in families: Johnny is an alcoholic, just like his dad and his dad before him. But how important is heredity? Do we learn bad -- and good -- habits from our parents, or are they preprogrammed in us, passed down in our genetic makeup?

This is the same question medical researchers have been trying to answer for many years. Every now and again, someone makes a small discovery that helps us understand who we are and what made us that way. New research presented here at the 153rd annual meeting of the American Psychiatric Association (APA) does just that.

According to researcher Patricia I. Ordorica, MD, something called OPRMI -- a particular genetic version of a molecule known to trap chemical impulses in the brain -- may explain why some people are more prone to become hooked on alcohol. In a recent study, Ordorica examined a group of alcoholics and found they are 2.5 times more likely to have the bad version of the OPRMI gene than are nonalcoholics -- including people who never drink as well as those who drink socially but don't get addicted.

Investigators are also curious to know whether a genetic tendency to alcoholism might make a person more likely to become addicted to other substances, such as tobacco. Therefore, Ordorica and her colleagues looked at whether the addiction-connected form of OPRMI was commonly found in smokers.

Importantly, they found that smokers were no more likely to have the substance in their bodies, which seems to mean that this particular gene is specifically connected to alcoholism.

"[T]hese results are another reason to be optimistic about our increasing knowledge of the major public health problem of alcoholism," says Ordorica, who is associate chief of staff for mental health and behavioral sciences at the Tampa VA Medical Center and director of addictive disorders at the University of South Florida.

"Although we are learning that genetic factors [are] important in the development of this illness, a lot of people still think that these are bad people," she says. "While no one gene causes alcoholism, genetic factors clearly account for a significant amount of the risk for the development of alcoholism."

Genetic research on alcoholism adds to the understanding of the illness and also points out its complexity, the APA's outgoing president Allan Tasman, MD, tells WebMD. Tasman, who has a background in addiction research, was not involved in Ordorica's study.

"We don't know whether a genetic deficit has been passed on," he says, "or if it's the environment, or some combination of the two." His hunch is that it's unlikely that just one gene is responsible for making someone an alcoholic. It's much more likely, he says, that several genetic traits are involved and work together to lead to the disease.